Cu(OTf)₂-Catalyzed Pummerer Coupling of β-Ketosulfoxides

Area of Science:

• Organic Chemistry
• Heterocyclic Chemistry
• Catalysis

Background:

• The Pummerer reaction is a valuable transformation in organic synthesis.
• Developing efficient methods for synthesizing substituted furan and benzofuran heterocycles is of significant interest.
• Copper(II) trifluoromethanesulfonate is a Lewis acid catalyst with potential applications in various organic reactions.

Purpose of the Study:

• To report a novel copper(II) trifluoromethanesulfonate-catalyzed Pummerer reaction.
• To explore the reaction's utility with β-ketosulfoxides and various π-nucleophiles.
• To provide an efficient synthetic route to polysubstituted 3-alkylthiofuran and 3-thiobenzofuran heterocycles.

Main Methods:

• Utilized copper(II) trifluoromethanesulfonate as a catalyst.
• Employed β-ketosulfoxides as starting materials.
• Reacted with π-nucleophiles including 1,3-dicarbonyl compounds, phenols, arenes, and tetraallylsilane.

Main Results:

• Successfully catalyzed the Pummerer reaction between β-ketosulfoxides and diverse π-nucleophiles.
• Achieved efficient synthesis of novel polysubstituted 3-alkylthiofuran derivatives.
• Demonstrated the formation of polysubstituted 3-thiobenzofuran heterocycles.

Conclusions:

• The reported copper-catalyzed Pummerer reaction offers a mild and efficient method for heterocycle synthesis.
• This methodology provides access to previously inaccessible polysubstituted 3-alkylthiofuran and 3-thiobenzofuran scaffolds.
• The use of readily available starting materials makes this approach practical for synthetic chemists.